N-Alkyl-pyrrolidones can act as solvents, surfactants, dispersants, detergents and emulsifiers, and thus are useful in a wide variety of applications. N-Alkyl-pyrrolidones are components, for example, in cleaners such as industrial, metal and surface cleaners, paint strippers, printing inks, gasoline and oil additives, industrial coatings and detergents. N-Alkyl-pyrrolidones are also useful in oil and gas well maintenance, polymer synthesis, photoresist applications, agricultural and pharmaceutical manufacture and paper manufacture.
U.S. Patent Appl. No. 2005/0054861 describes a process for producing 5-methyl-N-alkyl-2-pyrrolidone by a) reacting α-angelica lactone with alkyl amines, and b) hydrogenating the products of step (a) in the presence of a metal catalyst. α-Angelica lactone has limited availability and thus does not represent a cost-effective starting material for this reaction.
U.S. Patent Appl. No. 2004/0192933 describes a one-step process for preparing 5-methyl-1-R1-2-pyrrolidone comprising contacting levulinic acid with a primary amine.
The present invention provides an alternative method for preparing 5-methyl-N-alkyl-2-pyrrolidone.